Vim: Update Installation Batch Script

[ayushxx7]

• Test the state of the current installer (should be working for the most part)
• Fix issues related to post-install steps
• Separate Installers for Neovim & Gvim
• Decide if I want to continue supporting Gvim since I spend most of my time in nvim (personal machine), but the office's machines use gvim. Especially because of the problem related to undo history.
• Once it looks like the installer is stable, update office machines with the latest config

[ayushxx7]

found issues with Windows 7 (32-bit) Machine. There is no service pack installed on that machine.

• I could not install chocolatey on it
• Could not install the latest node.js manually. Had to install node 13.1. Had to install yarn so as to use :CocInstall
• Also, if vim is not in the path, then the vim -s command to install plugins does not work (this is resolved via: https://github.com/ayushxx7/dotfiles/commit/f07c1ab9355a4345da4e344f0518ada58841fa0c)

Overall, the rest of the installer worked as expected.

Maybe, I can pack fallback exes in case of installation fails & add commands in the batch script to set environment variables as well.